Remedy for overactive bladder comprising acetic acid anilide derivative as the active ingredient

ABSTRACT

(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]ethyl]acetic acid anilide or its salt shows a potent bladder relaxation effect in “isolated rat bladder smooth muscle relaxation test”, dose-dependently lowers the contraction frequency of rhythmic bladder contractions in “rat rhythmic bladder contraction measurement test” and, moreover, prolongs the urination intervals in “urination functions measurement test on cyclophosphamide-induced overactive bladder model rat”. Owing to these effects, the above compound is useful as a remedy for overactive bladder.

TECHNICAL FIELD

This invention relates to a remedy for overactive bladder comprising(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]ethyl]aceticacid anilide or a salt thereof as an active ingredient.

BACKGROUND ART

Bladder of mammals is under a dual control of autonomic nerve anddetrusor relaxes via an adrenaline β receptor by stimulation ofsympathetic nerve upon urination while, upon excretion of urine, itcontracts via a muscarine receptor by stimulation of parasympatheticnerve. As a remedy for overactive bladder resulted when the dual controlas such is unbalanced, anticholinergic agents such as propiverinehydrochloride and oxybutynin hydrochloride have been mostly used atpresent. However, there are intractable cases showing resistance to suchcompounds and there are side effects caused by anticholinergic agentssuch as urinary dysfunction and dry mouth and, therefore, it is thecurrent status that satisfactory clinical results are not alwaysachieved.

Further, as a result of increase in population of aged people in recentyears, numbers of patients suffering from overactive bladder areincreasing year by year and, in view of QOL (quality of life) ofpatients, there has been a brisk demand for the development of newdrugs.

The present inventors reported in Example 41 of a pamphlet ofInternational Laid-Open WO 99/20607 that(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]-ethyl]aceticacid anilide dihydrochloride has both promotion action for insulinsecretion and enhancing action for insulin sensitivity and further hasanti-obese and anti-hyperlipemic actions whereby it is a useful compoundfor the treatment of diabetes mellitus but there is neither suggestionnor disclosure for the therapeutic use for overactive bladder (refer toPatent Document 1).

In the meanwhile, in a pamphlet of International Laid-Open WO 98/07445,as an agent for prevention and treatment of urinary frequency andurinary incontinence containing a drug having stimulating action to aβ₃-adrenaline receptor as an active ingredient, there is mentioned thatCGP-12,177A represented by the following chemical structural formula hasa relaxation action for bladder (refer to Patent Document 2).CGP-12,177A has been known as a selective drug having stimulating actionto a β₃-adrenaline receptor (refer to Non-Patent Documents 1 and 2).

In a pamphlet of International Laid-Open WO 99/31045, compoundsrepresented by the following formula are mentioned as having astimulating action to a β₃-adrenaline receptor and as an agent forprevention or treatment of diseases caused by obesity, hyperglycemia andacceleration of movement of intestinal tract and diseases caused byurinary frequency or urinary incontinence, melancholia, biliary calculusor acceleration of bile duct movement (refer to Patent Document 3).

(In the formula, R¹ is hydroxyl group, a lower alkyl group, an aralkoxygroup, amino group, etc.; R² is hydroxyl group or a lower alkyl group;R³ is hydrogen atom or halogen atom; R⁴ and R⁵ each is hydrogen atom,halogen atom or a lower alkyl group; and A is a lower alkylene group.)

In a pamphlet of International Laid-Open WO 99/52856, compoundsrepresented by the following formula are mentioned as having astimulating action to a β₃-adrenaline receptor and as an agent forprevention or treatment of diseases caused by obesity, hyperglycemia andacceleration of movement of intestinal tract and diseases caused byurinary frequency or urinary incontinence, melancholia, biliary calculusor acceleration of bile duct movement (refer to Patent Document 4).

(In the formula, R¹ is hydrogen atom, a lower alkyl group or an aralkylgroup; R² is hydrogen atom, a lower alkyl group or halogen atom; and Ais oxygen atom or imino group.)

In a pamphlet of International Laid-Open WO 00/02846, compoundsrepresented by the following formula are mentioned as having astimulating action to a β₃-adrenaline receptor and as an agent forprevention or treatment of diseases caused by obesity, hyperglycemia andacceleration of movement of intestinal tract and diseases caused byurinary frequency or urinary incontinence, melancholia, biliary calculusor acceleration of bile duct movement (refer to Patent Document 5).

(In the formula, R¹ is hydroxyl group, etc.; one of R² and R³ ishydrogen atom, halogen atom, etc. and another is hydrogen atom; and R⁴is halogen atom, etc.)

-   Patent Document 1: Pamphlet of International Laid-Open WO 99/20607-   Patent Document 2: Pamphlet of International Laid-Open WO 98/07445-   Patent Document 3: Pamphlet of International Laid-Open WO 99/31045-   Patent Document 4: Pamphlet of International Laid-Open WO 99/52856-   Patent Document 5: Pamphlet of International Laid-Open WO 00/02846-   Non-Patent Document 1: Drugs of the Future, 1993, volume 18, no. 6,    page 542-   Non-Patent Document 2: The American Society for Pharmacology and    Experimental Therapeutics, 1993, volume 44, page 1100

DISCLOSURE OF THE INVENTION

The present inventors have carried out intensive studies for finding newpharmacological effects of(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]-ethyl]aceticacid anilide or a salt thereof (hereinafter, referred to as “the activeingredient of the present invention”) which is useful as a remedy fordiabetes mellitus and, as a result, they have found that the activeingredient of the present invention is useful as a remedy particularlyfor overactive bladder. In the present invention, overactive bladder isdefined as a disease by which urinary urgency is frequently resulted.Although benign prostatic hyperplasia is exemplified as one of thecauses for overactive bladder, there are many cases where the cause isambiguous and they are called idiopathic overactive bladder. Althoughoveractive bladder is sometimes accompanied by urinary frequency andurinary incontinence, it is not limited to the disease which is alwaysaccompanied by urinary frequency and urinary incontinence. Thus, in thecase of mild overactive bladder, a patient is sensitive to the sense ofwishing to urinate and frequently has a sense of wishing to urinate but,actually, he/she is able to hold his/her urine for a while. However,even in the case of a mild overactive bladder, its improvement has beenstrongly demanded in view of QOL (quality of life) of a patient. On theother hand, a severe overactive bladder is sometimes accompanied byurinary frequency and urinary incontinence. Urinary frequency is a statewhere number of times of urination is more than the normal one and issaid to be not less than about two times at night and not less thanabout 8 times during 24 hours. In urinary incontinence, there is aninvoluntary leakage of urine and that is defined as a state where thereis a problem socially or hygienically and is classified into stressurinary incontinence which occurs when abdominal pressure is appliedsuch as cough and sneeze, urinary urge incontinence where a desire tourinate suddenly occurs and urine leaks before arriving at the toiletand urinary incontinence of a mixed type where both stress urinaryincontinence and urinary urge incontinence are present.

The characteristic feature of the present invention is that the activeingredient of the present invention mitigates especially the frequentoccurrence of urinary urgency of a patient and number of times ofurination and state of urination are made into a more normal state. Itgoes without saying that overactive bladder in the present inventionincludes not only that as a result of benign prostatic hyperplasia butalso that accompanied with urinary urgency, urinary incontinence andpollakiuria.

In Patent Document 1, the active ingredient of the present invention isuseful, in addition to treatment of diabetes, as an agent for preventionand treatment of other diseases where an improvement in symptom is ableto be achieved by reducing the symptom of obesity and hyperlipemia suchas arteriosclerosis, ischemic cardiac disease such as cardiac infarctionand angina pectoris, brain artery sclerosis such as cerebral infarction,aneurysm, etc. However, there is neither description nor suggestion atall to the effect that the active ingredient of the present invention isuseful as a remedy for overactive bladder.

In Patent Document 2, use for overactive bladder is not mentioned aswell. In Patent Document 2, there is a description that only CGP-12,177Ahas a relaxation action to bladder as a compound having a selectivestimulating action to a β₃-adrenaline receptor. However, as comparedwith CGP-12,177A, the active ingredient of the present invention has farstronger relaxation action for bladder. In addition, in Patent Document2, there is no description for in vivo tests showing the usefulness forthe treatment of overactive bladder such as “rat rhythmic bladdercontraction measurement test” and “urination function measurement teston cyclophosphamide-induced overactive bladder model rat”.

Further, use for overactive bladder is not mentioned in Patent Documents3 to 5 as well. Compounds mentioned in Patent Documents 3 to 5 and theactive ingredient of the present invention are different in theirfundamental structures in such respects that the compounds mentioned inthe documents always have a phenol ring but have no thiazole ring andalso have no amide bond. In addition, in Patent Documents 3 to 5, thereis no description for in vivo tests showing the usefulness for thetreatment of overactive bladder such as “rat rhythmic bladdercontraction measurement test” and “urination function measurement teston cyclophosphamide-induced overactive bladder model rat”.

The present invention will now be illustrated in detail as hereunder.

In the present invention,(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]ethyl]aceticacid anilide or a salt thereof is an active ingredient. Thecharacteristic feature of the present invention is that the activeingredient of the present invention has been found to be useful as aremedy for overactive bladder which is a new use.

It is particularly preferred that the active ingredient of the presentinvention is a free base having no salt. However, it may form a saltwith an acid and examples of the salt are acid addition salts with amineral acid such as hydrochloric acid, hydrobromic acid, hydroiodicacid, sulfuric acid, nitric acid and phosphoric acid and an organic acidsuch as formic acid, acetic acid, propionic acid, oxalic acid, malonicacid, succinic acid, fumaric acid, maleic acid, lactic acid, malic acid,citric acid, tartaric acid, carbonic acid, picric acid, methanesulfonicacid, ethanesulfonic acid and glutamic acid. The active ingredient ofthe present invention having a salt may be easily manufactured from afree base by a common salt-forming reaction. The active ingredient ofthe present invention further includes hydrate, solvate andpolymorphism. The active ingredient of the present invention stillfurther includes pharmacologically acceptable prodrug. With regard to agroup for forming the prodrug, that mentioned in Prog. Med. 5,2157-2161(1986) and“Iyakuhin no Kaihatsu” (Development of Drugs)(Hirokawa Shoten, 1990), volume 7, Molecule Design, 163-198 may beexemplified.

The drug containing the active ingredient of the present invention maybe in any of forms of oral administration by tablets, pills, capsules,granules, diluted powder, etc. and parenteral administration byinhalant, etc. As to a solid composition for oral administration,tablets, diluted powder, granules, etc. are used. In the solidcomposition as such, one or more active ingredient(s) is/are mixed withat least one inert excipient such as lactose, mannitol, glucose,hydroxypropyl cellulose, microcrystalline cellulose, starch,polyvinylpyrrolidone and magnesium metasilicate aluminate. Thecomposition may contain an inert additive such as lubricant (e.g.,magnesium stearate), disintegrating agent (e.g., carboxymethyl starchsodium), solubilizing agent, etc. by a common method. Tablets and pillsmay, if necessary, be coated with sugar coat or with an intragastric orenteric coating agent. Dose may be appropriately decided for each casetaking symptom, age and sex of the subject to be administered, etc. intoconsideration. Usually, it is about 0.01 mg/kg to 100 mg/kg per day foran adult in the case of oral administration and is administered eitherat one time or by dividing into two to four.

The active ingredient of the present invention is able to be easilymanufactured by a method mentioned in Patent Document 1 but, sincemethod for the manufacture of a free substance which is preferred as theactive ingredient of the present invention is not specifically mentionedtherein, such a manufacturing method is shown in Manufacturing Examples.Route for the manufacture is illustrated as follows.

Manufacturing Examples Manufacturing Method for the Active Ingredient ofthe Present Invention Step 1

To a mixture of 5.90 kg of 4-nitrophenylethylamine monohydrochloride,4.43 kg of (R)-mandelic acid, 2.94 kg of triethylamine and 22 liters ofN,N-dimethylformamide were added 3.93 kg of hydroxybenztriazole and 5.58kg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide monohydrochloride(EDC) followed by stirring at about room temperature for 2 hours. EDC(0.28 kg) was further added thereto and the mixture was stirred at aboutroom temperature throughout one night. The reaction solution was dilutedwith 110 liters of water and extracted with ethyl acetate (60 liters, 30liters). The organic layer was successively washed with 60 liters of 1 Maqueous hydrochloric acid, 60 liters of 20% aqueous solution ofpotassium carbonate and water (60 liters, 60 liters) and concentrated invacuo at 10 to 19° C. The residue was dissolved in 35 liters of toluenewith heating at 87° C., cooled and stirred at 20° C. throughout onenight. The resulting crystals were filtered and washed with 10 liters oftoluene. This was dried in vacuo to give 7.66 kg of(R)-2-hydroxy-N-[2-(4-nitrophenyl)ethyl]-2-phenylacetamide as lightyellow crystals.

¹H-NMR (DMSO-d₆, 400 MHz) δ (ppm)=2.87 (2H, t, J=7.2 Hz), 3.30-3.46 (2H,m), 4.85 (1H, d, J=4.8 Hz), 6.12 (1H, d, J=4.8 Hz), 7.20-7.33 (5H, m),7.40 (2H, d, J=8.0 Hz), 8.04-8.12 (3H, m). FAB-MS m/z: 301 (M+H)⁺.

Step 2

A mixture of 7.51 kg of(R)-2-hydroxy-N-[2-(4-nitrophenyl)ethyl]-2-phenylacetamide, 23 liters of1,3-dimethyl-2-imidazolidinone and 23 liters of tetrahydrofuran wascooled at −18° C. and 49.4 kg of 1 M boran-tetrahydrofuran solution wasdropped thereinto at not higher than −7° C. After that, temperature ofthe mixture was raised to 70° C. followed by stirring for 5 hours. Thereaction mixture was cooled at −12° C. and 2.9 kg of methanol and 5.9 kgof concentrated hydrochloric acid were added thereto at not higher than5° C. After stirring at 68° C. for 1 hour, the mixture was concentratedin vacuo until the amount became 50 liters. A 30% aqueous solution (60kg) of K₂CO₃ and 6 liters of water were added thereto followed byextracting with 75 liters of ethyl acetate. The organic layer was washedwith 75 liters of water and concentrated in vacuo. Isopropanol (75liters) was added to the residue, the mixture was dissolved at 40° C.and 2.46 kg of concentrated hydrochloric acid was added to crystallizefollowed by stirring at 23° C. throughout one night. The crystals werefiltered and washed with 38 liters of isopropanol. They were dried invacuo to give 7.29 kg of(R)-2-[[2-(4-nitrophenyl)ethyl]amino]-1-phenylethanol monohydrochloride.

¹H-NMR (DMSO-d₆, 400 MHz) δ (ppm)=3.00-3.08 (1H, m), 3.15-3.30 (5H, m),5.00-5.05 (1H, m), 6.23 (1H, d, J=4.0 Hz), 7.29-7.35 (1H, m), 7.36-7.43(4H, m), 7.57 (2H, d, J=8.4 Hz), 8.21 (2H, d, J=8.4 Hz), 9.12 (2H, br).FAB-MS m/z: 287 (M+H)⁺.

Step 3

A mixture of 11.0 kg of(R)-2-[[2-(4-nitrophenyl)ethyl]amino]-1-phenylethanol monohydrochloride,110 liters of methanol and 1.20 kg of wet 10% palladium-carbon (wettingrate: 54.2%) was stirred in a hydrogen atmosphere until absorption ofhydrogen stopped. The reaction solution was filtered and the filtratewas concentrated in vacuo. Methanol (40 liters) was added to the residueto dissolve at 40° C. and crystallization was conducted by addition of220 liters of diisopropyl ether thereto followed by stirring at 20° C.throughout one night. The crystals were filtered and washed with 30liters of diisopropyl ether. They were dried in vacuo to give 9.43 kg of(R)-2-[[2-(4-aminophenyl)ethyl]amino]-1-phenylethanol monohydrochloride.

¹H-NMR (DMSO-d₆, 400 MHz) δ (ppm)=2.76-2.90 (2H, m), 2.95-3.16 (4H, m),4.95-5.11 (3H, m), 6.20 (1H, d, J=4.0 Hz), 6.53 (2H, d, J=8.4 Hz), 6.89(2H, d, J=8.4 Hz), 7.28-7.43 (5H, m), 8.97 (1H, br), 9.29 (1H, br).FAB-MS m/z: 257 (M+H)⁴.

Step 4

1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide monohydrochloride (EDC)(5.76 g) was added to a mixture of 8.00 g of(R)-2-[[2-(4-aminophenyl)ethyl]amino]-1-phenylethanol monohydrochloride,4.32 g of 2-aminothiazol-4-yl acetic acid, 2.64 g of concentratedhydrochloric acid and 120 ml of water at room temperature followed bystirring for 1 hour. A mixed solution of 2.40 g of sodium hydroxide and40 ml of water was dropped into the reaction solution to crystallize.The resulting crystals were filtered, washed with water and dried invacuo to give 9.93 g of(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]-ethyl]aceticacid anilide (hereinafter, referred to as “compound A”).

¹H-NMR (DMSO-d₆, 500 MHz) δ (ppm)=1.60 (1H, s), 2.59-2.66 (4H, m),2.68-2.80 (2H, m), 3.45 (2H, s), 4.59 (1H, br), 5.21 (1H, br), 6.30 (1H,s), 6.89 (2H, s), 7.11 (2H, d, J=8.5 Hz), 7.19-7.23 (1H, m), 7.27-7.33(4H, m), 7.49 (2H, d, J=8.5 Hz), 9.99 (1H, s). FAB-MS m/z: 397 (M+H)⁺.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will now be specifically illustrated by way of thefollowing Examples but the present invention is not limited to thecontent thereof.

Example 1 Isolated Rat Bladder Smooth Muscle Relaxation Test Test Method

The test was conducted by referring to The Journal of Urology, 1999,volume 161, page 680.

Male rats of Wistar strain of 10 to 11 weeks age were sacrificed bydepletion, whole bladder was isolated by laparotomy and bladder sectionseach being in a size of about 3×10 mm were prepared in a nutrientsolution which was well oxygenated with 95% O₂ and 5% CO₂(Krebs-Henseleit solution (118.4 mM NaCl, 4.7 mM KCl, 1.2 mM KH₂PO₄; 1.2mM MgSO₄, 2.5 mM CaCl₂, 25.0 mM NaHCO₃ and 11.1 mM glucose)). Thesection was hung in a Magnus tube in which a nutrient solution(Krebs-Henseleit solution) of 37° C. into which 95% O₂ and 5% CO₂ wereaerated, stabilized for 30 to 60 minutes with a load of 1 g and 10⁻⁶ Mcarbachol (CCh) or 40 mM potassium chloride (KCl) was repeatedly appliedthereto whereupon it was confirmed that reactivity to CCh or KCl becamealmost constant. After contractionby 10⁻⁶ M CCh or 40 mM KCl was inducedand the generated tension was stabilized, a test drug (compound A orCGP-12, 177A) was cumulatively administered in 10-fold ratio withintervals of about 10 minutes and the relaxation reaction was observed.After completion of observation of relaxation reaction at maximumconcentration of the test drug, 10⁻⁴ M papaverine was added to inducethe maximum relaxation and a relaxation rate was calculated where therelaxation reaction was defined as 100%.

Results

As a result of the above test, the compound A which is the activeingredient of the present invention showed a strong relaxation action inantagonism test to contractionby carbachol and antagonism test tocontraction by potassium chloride in an isolated rat bladder smoothmuscle relaxation test. In addition, the compound A showed asignificantly strong relaxation action as compared with CGP-12,177A(control compound).

Relaxation rates to drug concentration of the compound A which is theactive ingredient of the present invention and the control compound areshown in FIG. 1 (antagonism test to contraction by carbachol) and FIG. 2(antagonism test to contraction by potassium chloride), respectively.Further, EC₅₀ and maximum relaxation rate of the test drug in theantagonism test to contraction by carbachol are shown in Table 1 whileconcentration comparison of the compound A expressing the maximumrelaxation rate of CGP-12,177A is shown in Table 2.

The compound A showed an action strength of 270-fold as compared withthe CGP-12,177A (control compound). Similarly, EC₅₀ and maximumrelaxation rate of the test drug in the antagonism test to contractionby potassium chloride are shown in Table 3 while concentrationcomparison of the compound A expressing the maximum relaxation rate ofCGP-12,177A is shown in Table 4. The compound A showed an actionstrength of 383-fold as compared with the CGP-12,177A (controlcompound).

TABLE 1 EC₅₀ and maximum relaxation rate of the test drug in theantagonism test to contraction by carbachol Test Drug EC₅₀ (M) MaximumRelaxation Rate (%) Compound A 5.2 × 10⁻⁶ 94.0 (Active Ingredient of thePresent Invention) CGP-12, 177A >10⁻⁴ 15.7 (Control Compound)

TABLE 2 Concentration comparison of the compound A expressing themaximum relaxation rate of CGP-12, 177A in antagonism test tocontraction by carbachol Comparison of Test Drug Concentration (M)Action Strength* Compound A 3.7 × 10⁻⁷ 270 (Active Ingredient of thePresent Invention) CGP-12, 177A 10⁻⁴ 1 (Control Compound) *Compared inthe concentration where the compound showed a relaxation rate of 15.7%

TABLE 3 EC₅₀ and maximum relaxation rate of the test drug in theantagonism test to contraction by potassium chloride Test Drug EC₅₀ (M)Maximum Relaxation Rate (%) Compound A 1.1 × 10⁻⁵ 69.1 (ActiveIngredient of the Present Invention) CGP-12, 177A >10⁻⁴ 17.4 (ControlCompound)

TABLE 4 Concentration comparison of the compound A expressing themaximum relaxation rate of CGP-12, 177A in antagonism test tocontraction by potassium chloride Comparison of Test Drug Concentration(M) Action Strength* Compound A 2.6 × 10⁻⁷ 383 (Active Ingredient of thePresent Invention) CGP-12, 177A 10⁻⁴ 1 (Control Compound) *Compared inthe concentration where the compound showed a relaxation rate of 17.4%

Example 2 Rat Rhythmic Bladder Contraction Measurement Test Test Method

The test was conducted by referring to European Journal of Pharmacology,2000, volume 407, page 175.

1. Measuring Method

Female rats (225 to 290 g) of Wistar strain was used for the test. Underanesthetization with urethane, right and left ureters were ligated andcut and, after that, a polyethylene cannula was inserted from externalurinary meatus and fixed. One end of the fixed cannula was connected toa pressure transducer via a three-way cock and pressure in the bladderwas measured. Another end thereof was connected to a syringe pump and aphysiological saline solution was continuously infused at a constantrate into bladder whereupon rhythmic bladder contraction was induced.The continuous infusion of a physiological saline solution was stoppedafter a rhythmic bladder contraction was noted. After the rhythmicbladder contraction was stabilized, drug or vehicle was administeredfrom a catheter for administration of drug inserted into femoral vein.

2. Drug

The compound A was intravenously administered in increased doses wherethe ratio was 3 (0.03, 0.1, 0.3, 1 and 3 mg/kg). A group to whichvehicle was administered was used as a control group.

3. Evaluated Items and Statistical Analysis

Parameters for evaluation were number of times and contraction pressureof bladder contraction during 10 minutes from 5 to 15 minutes after theadministration of the drug and each group was conducted in n=5. Theresult is shown in terms of mean value±standard error and Student t-testwas conducted for comparison between the two groups.

Results

By intravenous administration of the compound A, contraction frequencyof rhythmic bladder contraction decreased on a dose-dependent manner(FIG. 3). An action of decreasing the contraction frequency byintravenous injection (i.v.) of 3 mg/kg of the compound A wassignificant as compared with the control group. On the other hand, thecompound A did not affect the contraction pressure until intravenousadministration of 3 mg/kg (FIG. 4). The fact of no influence on thecontraction pressure is a preferred property from the viewpoint thaturinary retention is not induced or that residual urine is not resultedupon urination.

A suppressive effect for contraction frequency by the compound A ispresumed to be due to an increase in bladder volume by stimulation ofthe compound A for a β₃ receptor existing in the bladder. It has beenbelieved that an increase in functional bladder volume showing the urinevolume which is able to be stored in the bladder is clinically usefulfor the treatment of patients suffering from overactive bladder and,therefore, the compound A is believed to be clinically effective as aremedy for overactive bladder.

Example 3 Test for Measurement of Urination Function of Model RatSuffering from Overactive Bladder Induced by Cyclophosphamide

Overactive bladder model rats induced by cyclophosphamide were preparedby referring to British Journal of Pharmacology, 2000, volume 130, page331 and the following test was conducted.

Test Method 1. Measuring Method

Female rats (220 to 230 g) of Wistar strain were used for the test.Under anesthetization with pentobarbital sodium, a catheter for infusionof physiological saline solution and for measurement of pressure inbladder was inserted into bladder from the top of the bladder and fixedwhile a catheter for administration of a drug was inserted into carotidvein and fixed. Cyclophosphamide (CYP) was administered into abdominalcavity and, after being recovered, the rats were returned to a feedingcage. On the next day of the operation, one end of the catheter insertedinto bladder of the rat was connected to a syringe pump via a three-waycock and a physiological saline solution was continuously infusedwhereby |micturition| reflex was induced. Another end was connected to apressure transducer and pressure in the bladder was measured. After themicturition reflex was stabilized, 1 mg/kg of the compound A wasadministered from a catheter for administration of drug which wasinserted into carotid vein.

2. Evaluated Items and Statistical Analysis

Parameter for the evaluation was an average interval for urination fromadministration of the drug until 30 minutes thereafter. The result wasshown in terms of an average urination interval after administration ofthe drug to the average urination interval before administration of thedrug where an average urination interval during 30 minutes beforeadministration of the drug was defined 1000 and was shown in a meanvalue of n=3.

Results

As a result of intravenous administration of the compound A (1 mg/kg),micturition interval of overactive bladder model rats induced bycyclophosphamide was elongated to an extent of 17.3% (FIG. 5). From sucha fact, the compound A which prolongs the micturition interval of thepresent model rats is believed to be clinically effective as a remedyfor overactive bladder.

Thus, the active ingredient of the present invention shows a strongbladder relaxation action in “isolated rat bladder smooth musclerelaxation test”, decreases the contraction frequency of rhythmicbladder contraction on a dose-depending manner in “rat rhythmic bladdercontraction measurement test” and prolongs the micturition interval in“micturition function measurement test on cyclophosphamide-inducedoveractive bladder model rat” whereby it is clinically useful as aremedy for overactive bladder. In addition to overactive bladder as aresult of benign prostatic hyperplasia, it is also able to be used as aremedy for overactive bladder accompanied with urinary urgency, urinaryincontinence and pollakiuria.

Example 4 Formulation Example Formulation Example for Oral Agent

TABLE 5 Composition Tablet Active ingredient of the present invention100.0 mg Lactose 199.5 mg Corn starch 40.0 mg Hydroxypropyl cellulose9.0 mg Magnesium stearate 1.5 mg Subtotal 350 mg Coat Hydroxypropylmethyl cellulose 2910 8.7 mg Polyethylene glycol 6000 1.2 mg Titaniumoxide 4.8 mg Talc 0.3 mg Subtotal 15 mg Grand total 365 mg

100-mg Tablet

The active ingredient of the present invention (200.0 g) and 399.0 g oflactose were mixed in a polyethylene bag. The mixture was mixed anddisintegrated in a sample mill (manufactured by Hosokawa Micron). Thedisintegrated mixture (450.0 g) and 60.1 g of corn starch were uniformlymixed in a fluidized granulation coating apparatus (manufactured byOgawara Seisakusho). A 10% hydroxypropyl cellulose solution (192 g) wassprayed thereon to granulate. After being dried, the above was passedthrough a sieve of 20 meshes, 2.3 g of magnesium stearate was addedthereto and the mixture was made into tablets each comprising 350 mg bya rotary tabletting machine (manufactured by Hata Tekkosho) using apounder of ¢9.0 mm×10.8 R. The tablets were sprayed with 150 g of acoating solution containing 8.7 g of hydroxypropyl methyl cellulose, 1.2g of polyethylene glycol 6000, 4.8 g of titanium oxide and 0.3 g of talcin a coating apparatus (manufactured by Freund Sangyo) to givefilm-coated tablets each being coated with 15 mg.

INDUSTRIAL APPLICABILITY

As mentioned hereinabove,(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]ethyl]aceticacid anilide or a salt thereof which is an active ingredient of thepresent invention showed a significantly strong relaxation action ascompared with the control compound in “isolated rat bladder smoothmuscle relaxation test”. Further, it decreased the contraction frequencyof rhythmic bladder contraction on a dose-dependent manner in “ratrhythmic bladder contraction measurement test”. Still further, itprolonged the micturition interval of cyclophosphamide-inducedoveractive bladder model rat in “micturition function measurement teston cyclophosphamide-induced overactive bladder model rat”.

Accordingly,(R)-2-(2-Aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]ethyl]aceticacid anilide or a salt thereof which is an active ingredient of thepresent invention is able to be used as a remedy for overactive bladder.In addition to overactive bladder as a result of benign prostatichyperplasia, it is also able to be used as a remedy for overactivebladder accompanied with urinary urgency, urinary incontinence andpollakiuria.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Effects of the compound A and the control compound to isolatedrat bladder smooth muscle relaxation test (antagonism test tocontraction by carbachol)

FIG. 2: Effects of the compound A and the control compound to isolatedrat bladder smooth muscle relaxation test (antagonism test tocontraction by potassium chloride)

FIG. 3: Effect of the compound A to rat rhythmic bladder contraction(effect to contraction frequency (*: p<0.05))

FIG. 4: Effect of the compound A to rat rhythmic bladder contraction(effect to contraction pressure)

FIG. 5: Effect of the compound A to micturition function ofcyclophosphamide-induced overactive bladder model rat (showing theurination interval after administration of a drug where the urinationinterval before administration of the drug was defined as 100%)

1-10. (canceled)
 11. A method for treating for overactive bladdercomprising administering an effective amount of(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]ethyl]aceticacid anilide or a salt thereof as an active ingredient to a subject inneed thereof.
 12. The method according to claim 11, wherein saidoveractive bladder is a result of benign prostatic hyperplasia.
 13. Themethod according to claim 11, wherein said subject has urinary urgency.14. The method according to claim 11, wherein said subject has urinaryincontinence.
 15. The method according to claim 11, wherein said subjecthas pollakiuria.
 16. A method for treating overactive bladder comprisingadministering an effective amount of a free base of(R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]ethyl]aceticacid anilide as an active ingredient to a subject in need thereof. 17.The method according to claim 16, wherein said overactive bladder is aresult of benign prostatic hyperplasia.
 18. The method according toclaim 16, wherein said subject has urinary urgency.
 19. The methodaccording to claim 16, wherein said subject has urinary incontinence.20. The method according to claim 16, wherein said subject haspollakiuria.